I have recently had this problem, and I have seen a few other people have to.. I think it was recently with the new patch update. Whenever I try to save, I get 'Error Code 12' which makes it unable to save. I've tried doing 'Save As..', and that's no different.

How can I fix this without losing any of my saves?

Some suggestions here: http://www.modthesims.info/wiki.php...TS3_Save_Errors

Sometimes using Reset Everything in Master Controller, pause the game, go to Map View, Save As... help you save for that time. But once it went wrong, it's going to be more and more painful if you insist to keep that save. I had to porter half of my town to a new world, maybe the save got bloated after a while, or CC, mods... went corrupted after a patch... Take a look at these suggestions:
http://crinrict-help.blogspot.com/s...abel/Error%2012

Install 64bit system. the ultimate solution I can assure you that.
Other walkarounds are just temporary, you will ending getting error 12 eventually under 32bit system as you play along.

I was desperate once.....but after installing 64bit win7....never occoured to me ever...

The only thing that worked for me is pause the game before saving each time. Weird but it's working for me

I had to download a mod to disable memories to make it go away. My saves were getting too large and error 12 was popping up every other save only a few weeks in any save game due to the memories.